54 MASSACHUSETTS HORTICULTURAL SOCIETY. 



various ingredients of plant food, the description being illustrated 

 bj a diagram, representing several buckwheat plants growing in 

 ditferent solutions of plant food, — one with all the ingredients 

 needed ; one with all but potash ; one with nitrogen omitted ; one 

 without phosphoric acid, and so on. It was found that if any one 

 essential ingredient was not supplied in sufficient quantity, the 

 plant would not grow. A solution containing all the necessary in- 

 gredients, is known as a normal solution. In such solutions plants 

 are raised as large, as healthy, and in every way as perfect as those 

 grown in the soil. Woltf raised in such a solution four perfect oat 

 plants with forty-six stems, and 1,535 well developed seeds. 

 Nobbe obtained a Japanese buckwheat plant, nine feet high, weigh- 

 ing, air-dry, 4,786-fold the weight of the seed, and bearing 796 

 ripe, and 108 imperfect seeds. And Professor Knop used to delight 

 in showing his friends a 3'oung oak tree, very small indeed, but the 

 growth of which had been normal, though its roots had been im- 

 mersed only in aqueous solutions. The results of a vast amount of 

 this sort of experimenting all point in one direction, and prove this 

 principle. 



No agricultural plant can attain full growth without a sufficient 

 supply, through its roots, from the soil, of potash^ lime, magnesia, 

 iron, pliosplioric acid, sulpthuric acid, and some compound of 

 nitrogen. 



Besides these, chlorine, and perhaps silica, are sometimes, if not 

 always, indispensable, though in very small proportions, to complete 

 development. If any one of these essential higredients be lacking, 

 the plant will suffer in growth and development. 



Such experiments as these, coupled with practical experience in 

 the field, have led to almost a revolution in our views of fertilizing. 

 We have learned that we must put on manure to feed plants. But 

 there are various important conditions of the successful working of 

 manure, among which are proper tillage and thorough mixing of the 

 fertilizers with the soil. The indirect action of fertilizers is a very 

 important point. 



Every soil, however barren, is capable of furnishing some plant 

 food. In what are called " worn-out soils," the available supply of 

 one or more ingredients is generally insufficient. 



In experiments with buckwheat plants grown in boxes of sand 

 taken from the well-known barren plains in Wallingford, Conn, (on 

 the line of the N. Y., N. H., & H. R. R.), the plants grown with- 



